Control apparatus



May 13, 1958 R. N. AUGER CONTROL APPARATUS Filed Dec. 1, 1955 INVENTOR RAYMOND IV. AUGER BY M M ATTORNEYS United States Patent CONTROL APPARATUS Raymond N. Auger, New York, N. Y. Application December 1, 1955, Serial No. 550,264

14 Claims. (Cl. 200-17) This invention relates to control apparatus, and more particularly, to apparatus for controlling the application of power.

In the design of machines of various types, it is sometimes necessary to employ apparatus for amplifying the torque or force of a signal in order that the signal may be utilized in the desired manner. Such mechanisms are sometimes referred to as torque amplifiers. They are useful wherever a low torque source is called upon to drive a relatively high torque device.

Another factor which is sometimes encountered in the design of machinery is the necessity for utilizing the movement of a driving member to produce a stepped or intermittent movement in a driven member. This type of conversion is desirable, for example, in apparatus for driving a rotary switch. The steps of the output motion may be made to correspond in extent to the spacing of the contacts of the switch so that rotary element will never stop intermediate adjacent contacts even though the input or driving movement may be irregular.

It is an object of the present invention to provide a force or torque amplifier which can be produced economically and which will be durable and efficient in operation.

Another object of this invention is to provide simple and reliable apparatus for converting input movements into a series of stepped output movements.

A more specific object of this invention is to provide a mechanical torque amplifier having a stepped output and being capable of operation in either direction of rotation.

Still another object of this invention is to provide switching apparatus in which the movable element is driven in stepped fashion to cooperate with a plurailty of spaced contacts.

The foregoing objects are accomplished according to one embodiment of the invention by the provision of a plurality of contacts spaced angularly about an axis, a rotary switch element cooperating with such contacts to complete different ones of a plurality of circuits, and a torque amplifier for driving the rotary switch element. The torque amplifier has an output shaft adapted to be rotated in one direction or the other by means of an output differential which includes two sources of mechanical power and means for releasing one or the other of these sources for predetermined amounts of angular movement. The release of power is accomplished by the use of latches and notched wheels. The latches normally prevent rotation of the notched wheels, but they may be released when desired.

The tripping of the latches is accomplished by a control link which is movable under the influence of an input differential. The input differential compares the angular position of an input shaft with the angular position of the output shaft, and any difference in such positions causes movement of the control link from its neutral position. When the movement of the control link is of 2,834,843 Patented May 13, less A l a predetermined extent, the link serves to trip one or the other of the latches. Then movement of the output shaft in response to the release of power returns the control link to its neutral position.

A better understanding of the invention and its many objects and advantages will be gained from a consideration of the following detailed description of an embodiment thereof illustrated in the accompanying drawings in which:

Fig. 1 is a diagrammatic perspective view of a rotary switch and torque amplifier according to the invention; and

Fig. 2 is a vertical sectional view taken approximately along the axes of the output and input shafts in Fig. 1.

In the drawings, the numeral 2 indicates a switch plate which may be of any known form. The switch plate 2 carries a plurality of pairs of contacts 4 and 6, spaced angularly about the central axis thereof. The contacts 4 and 6 of each pair are spaced from each other, as indicated by the numeral 8, so that a circuit, of which the contacts of the pair are a part, normally is open. However, the contacts 4 and 6 of a pair may be bridged by a rotary switch element ill to complete the circuit.

It is contemplated that a plurality of circuits be associated with the several pairs of contacts 4 and 6 to be controlled thereby. Hence, it will be seen that the angular position of the rotary switch element 10 determines which of the various circuits will be closed. This relationship is common to various known switching devices, and it will be evident to persons skilled in the art that the switching apparatus illustrated is merely an example of many to which the present invention is applicable. The known shaft-input analog-to-digital converters are similar, and they constitute commercially important examples.

The rotary switching element 10 is fixed, as by means of a set screw 12, to an output shaft 14 of a torque amplifier. The output shaft 14 is mounted for rotation in spaced apart frame members 16 and 18, and is driven.

by means of an output differential designated generally by the numeral 20.

The output differential 20 includes a first rotatable member 22, mounted for rotation relative to the output shaft 14 on a suitable bearing 24, and a second rotatable member 26, mounted for rotation relative to the output shaft 14 on a suitable bearing 28. The member 22 includes notched or toothed wheel 30 and a gear 32 spaced from the notched wheel 30. The member 26 is similar in that it includes a notched wheel 34 and a gear 36 spaced therefrom. The gears 32 and 36 are in engagement with a follower or spider gear 38, rotatably mounted on a radial arm 40 which is welded or otherwise secured at its inner end to the output shaft 14.

Forces are applied to the rotatable members 22 and r 26 tending to rotate these members in opposite directions.

In the illustrated embodiment of the invention, such forces are applied by power means in the form of weights 42 and 44 attached to the members 22 and 26 by flexible cords 46 and 48 wound about the central portions of the members 22 and 26 in opposite directions.

This particular power means was selected for. illustration because of its simplicity. It should be understood, however, that other power means may be employed if desired. For example, solenoid-wound springs, particularly those employing the one-pulse solenoid winding common in automobile clocks, would be quite suitable for use in place of the illustrated weights 42 and 44. Mainspring winding without interruption of operation may be accomplished by using two springs in series and applying the re-wind torque between them.

Cooperating with the notched wheels 30 and 34 of the rotatable members 22 and 26 are a pair of stop means or into holding engagement with the notched 'wheels'30'and" 34. With the parts in this position, no power is applied to the output shaft 14, and the rotary switchelement' remains stationary.

Extending between the latches 50 and 52 is a portion of a control link or trip arm 60. One 'end portion of. the control link 60'is fixed, by welding or otherwise, to a collar 62 which is rotatably mounted upon the output;

shaft 14 by means of a bearing 64. The collar '62,is biased to an angular position in which the control arm 60'is in a neutral position between the two latches 50 and 52 by means of a Weight 66. The weight 66 is adjustably mounted, as by means of a set screw 68, on a rod 70 fixed to the collar 62 at a point opposite the control link 60 By changing the distance of the weight 66 from the axis of rotation of the collar 62, the bias of the link 60 may be regulated.

The other end of the control link 60 has rotatably mounted thereon a spider or follower gear 72, which is a part ofan input differential designated generally by the numeral74. The spider gear 72 engages both a drive gear 76 and a feedback gear 78.

The feedback gear 78 is attached, as by means of a set screw 80,'to a feedback'shaft 82, supported by a frame member 84. The feedback shaft 82 is coupled to the output shaft 14 by means of a dead-space coupling 86 of any suitable design. Couplings of this type are well known in theart and need not be described in detail in this application. In the drawings, a space 88 has been shown to suggest the lag produced by the dead-space coupling between motion of the output shaft and motion of the feedback shaft.

In order to prevent thefeedback gear 78 from moving, except when driven by the output shaft 14 through the dead-space coupling 86, a spring 89 is attached to the frame of the apparatus and arranged to bear against the periphery ofv the gear 78. The spring 89 cooperates with the surface of the gear 78 to frictionally resist rotation of the gear 78. This frictional resistance is sufiicient to hold the gear 78 stationary, except when the gear is driven by the output shaft- 14.

The drive gear 76 is fixed, as by means of a set screw 90, to an input shaft 92, mounted for rotation in a frame.

portion 94. The input shaft 92.may be driven by any suitable means. Forthe sake of simplicity, the illustrated embodiment contemplates that the input shaft 92 may be moved manually. For this purpose, the end of the shaft 92 is provided with a knob 96 having-a pointer 98 associated therewith and arranged 1 to cooperate with indicia 100 on the face of the frame member 94.

The operation of the illustrated. embodiment of the invention now will be described in detail. Assuming first that the input shaft 92 is rotated in a clockwise direction, as viewed in Fig. 1. It will be evidentv that the angular movement of the drive .gear 76 will:tend tocause the spider 72 to walk or move about the axis of the stationary feedback gear 78.

As the spider gear 72 moves 'in this fashion, it, carries with it the control link.60' in a clockwise direction, as

viewed in Fig. 1, into a positionin which the control .link- 60 causes the latch 52 to pivot about the shaft 54 in a clockwise direction. of this description that movement of theinput shaft 92 ceases at this instant.

When the latch 52 releases its hold on .the.notched wheel 34, the weight 44 begins to descend, causing the rotatable member 26 to rotate in a clockwise direction.

The gear 36 then moves the-follower or spider gear 38" It can be assumed for the purposes-.:

spider gear 38 drives the radial arm 40 about the axis of the output shaft 14'to cause the output shaft to rotate in a clockwise direction in Fig. 1. This clockwise rotation of the output shaft is transmitted through the dead-space coupling 86 to the feedback shaft 82, and hence, to the feedback gear 78, which serves to return the input spider gear 72 to its original position.

If it is assumed that the inputshaft 92 is rotated in a counterclockwisedirection, as viewed in Fig. l, the operation will be very similar to that described above, except as to directions and. except that 'the latch50 instead of the latch 52, will be. released by the control link 60.

The operation of the torque amplifier in response to other types of input willnot vary materially from that described above. If, for example, the input is in the form of continuous rotation, the output shaft 14 will move in a series of steps like the step described above, with the appropriate one of the latches 50 or 52 being alternately released from and applied to the notched wheel cooperating therewith.

It should be noted at this point that, whatever the nature of the input may be, the output shaft 14 moves only in quick steps of definite angular extent corresponding to the spacing of the notches on the wheels 30 and 34. Therefore, the rotary switch element 10 moves rapidly between positions which correspond exactly with the positions of the pairs of contacts4 and 6. This type of operation is highly advantageous .in that arcing is minimized and reliability is enhanced.

The stepped or digital output of the torque amplifier of this invention is of particular significance. in many applications other than the rotary switching apparatus. For example, it may be used to drive counter mechanisms in such'a way that they show only full numerals, to position analog components to precise points, or to operate light-duty valves directly from pressure or temperature sensers.

Since various modifications and alterations will be apparent to persons skilled in the art,.the foregoing detailed description of an embodiment of the present invention is intended as an example only. The scope of the invention isto be ascertained from the following claims.

I claim:

1; The combination which comprises a movable member, a source-of mechanically stored energy operatively connected to said member and applying a-force to said member tending to cause said member to move, stopmeans movable between a first position in which it contacts said member to prevent movement of the member and a second position in which it is out of contact with said member, means for moving said stop means from said first position to said second position to free said movable member for motion under the influence of the force applied by said source of mechanically stored energy, and means operable in response to movement of said movable member for returning said stop means to said first position.

2. The combination which comprises arotatable member, 21 source of mechanicallystored energy for applying a force tending to rotate said member, stop-means mounted adjacent said member for movement between a first position in which it is in holding engagement with any one of a plurality of angularly spaced portions of the surface of said member to prevent rotation thereof and a second position in which it is out of holding engagement with respect to said member, means for moving said stop means from said first position to said second position to free said member for angular movement under the influence of said force, and means operating in response to angular movement of said member for returning said stop means to saidfirst position.

3. The combination which comprises a movable member having a plurality of teeth thereon, a source of mechanically stored energy operatively connected to said member for applying a force thereto tending to move said member, latch means mounted adjacent the path of movement of said teeth for movement between a first position in which it is in holding engagement with at least one of said teeth to prevent movement of said member and a second position in which it is out of holding engagement with said teeth, means for moving said latch means from said first position to said second position to free said movable member for movement under the influence of the force applied by said source of mechanically stored energy, and means operable in response to movement of said movable member for returning said latch means to said first position.

4. Switching apparatus comprising a plurality of con tacts mounted in angularly spaced relation about an axis, an element mounted for angular movement about said axis for cooperation with selected ones of said contacts, a rotatable member for moving said element, means for applying a force tending to rotate said member, stop means mounted adjacent said member for movement between a first position in which it is in holding engagement with any one of a plurality of angularly spaced portions of the surface of said member to prevent rotation thereof and a second position in which it is out of holding engagement with respect to said member, means for moving said stop means from said first position to said second position to free said member for angular movement under the influence of said force, and means operating in response to angular movement of said member for returning said stop means to said first position.

5. The combination which comprises a rotatable member, means for applying a force tending to rotate said member, stop means mounted adjacent said member for movement between a first position in which it is in holding engagement with any one of aplurality of angularly spaced portions of the surface of said member to prevent rotation thereof, and a second position in which it is out of holding engagement with respect to said member, means biasing said stop means toward said first position, a rotatable feedback element operatively connected to said rotatable member, a rotatable drive element, means engaging said elements and movable thereby in accordance with differences in the angular velocities of said elements, and a control link connected to the lastmentioned means for moving said stop means from its first to its second position upon angular movement of said drive element to free said member for angular movement and for permitting the return of said stop means to its first position upon angular movement of said feedback element.

6. A torque amplifier comprising an output shaft, first and second rotatable members each having a series of angularly spaced notches extending about the axis of rotation thereof, mechanical power means for applying forces to said members tending to rotate them, first and second latches associated respectively with said first and second rotatable members for normally holding said members stationary, means connecting said first and second members to said shaft for rotating said shaft in one direction upon rotation of said first member and in the opposite direction upon rotation of said second member, a rotatable feedback element, a dead-space cou pling between said feedback element and said output shaft, a rotatable drive element, means engaging said elements movable thereby in accordance with dilferences in the angular velocities of said elements, and a control link connected to the last-mentioned means for releasing either of said latches upon angular movement of said drive element to free the corresponding rotatable member for angular movement under the influence of said force and for permitting such latch to be re-applied upon angular movement of said feedback element.

7. The combination with a rotatable shaft of a mechanism for controlling the angular movement of said shaft,

said mechanism comprising a first rotatable member, a second rotatable member, power means operatively connected to said members for applying forces thereto tending to rotate each of said members, first stop means movable between a first position to which it is normally biased and in which it is in holding engagement with said first rotatable member to prevent rotation thereof and a second position in which it is out of holding engagement with said first rotatable member, second stop means movable between a first position to which it is normally biased and in which it is in holding engagement with said second rotatable member to prevent rotation thereof and a second position in which it is out of holding engagement with said second rotatable member, a control element movable along a path and being effective when moved to one end only of said path to move said first stop means from its first to its second position and effective when moved to the other end only of said path to move said second stop means from its first to its second position, means connecting said first and second members to said shaft for rotating said shaft in one direction upon rotation of said first member and in the opposite direction upon rotation of said second member, means for moving said control element along said path to move either of said stop means from its first to its second position, and means for returning said control element to the central portion of its path in response to rotation of said shaft.

8. Switching apparatus comprising a plurality of contacts mounted in angularly spaced relation about an axis, an element mounted for movement about said axis to a plurality of angularly spaced positions for cooperation with selected ones of said contacts, a shaft for driving said element, first and second rotatable members each having a series of angularly spaced notches extending about the axis of rotation thereof, means for applying forces to said members tending to rotate said members, first and second latches associated respectively with the notches of said first and second rotatable members, means connecting said first and second members to said shaft for rotating said shaft in one direction upon rotation of said first member and in the opposite direction upon rotation of said second member, and control means for said latches operable to release either of said latches to free the corresponding rotatable member for angular movement under the influence of said force and then to re-apply such latch to such rotatable member in response to angular movement of said shaft.

9. The combination which comprises a rotatable output shaft; an output differential including first and second rotatable members and means connected thereto for movement in accordance with any difference in the angular velocities of said members, said means being operatively connected to said shaft; power means for applying forces to said members tending to rotate them in opposite directions; first stop means mounted for piovtal movement between a first position to which it is normally biased and in which it is in holding engagement with said first member to prevent rotation thereof and a second position in which it is out of holding engagement with said first member; second stop means mounted for pivotal movement about a pivotal axis extending in substantially the same direction as the pivotal axis of said first stop means, said second stop means being movable between a first position to which it is normally biased and in which it is in holding engagement with said second member to prevent rotation thereof and a second position in which it is out of holding engagement with said second member; an input differential including a movable drive element, a movable feedback element connected to'said output shaft, and means connected to said elements for movement in accordance with any difference in the velocities of said elements; and a control link connected to the last-mentioned means for movement along a path between said step means for moving each of said stop means separately from its first to its second position.

10. A torque amplifier comprising a rotatable output shaft, first and second members rotatably mounted on said shaft in spaced apart relation, an arm fixed to said shaft and extending radially therefrom in the space between said members, a gear mounted on said arm for rotation about an axis perpendicular to the axis of said output shaft, said first and second members each having teeth thereon in engagement with the teeth of said gear and also having a series of regularly spaced notches extending around the circumference thereof, power means for applying forces to said members tending to rotate them in opposite directions, a first latch pivotally mounted adjacent the path of the notches on said first member, a second latch pivotally mounted adjacent the path of the notches on said second member, the pivotal axes of said latches being spaced from and parallel to the axis of said output shaft, means biasing each of said latches toward a position in which a portion thereof engages one of said notches, a trip arm mounted for angular movement about the axis of said output shaft and including a first portion located between portions of said latches spaced from the pivotal axes thereof and a second portion extending radially toward the extended axis of said output shaft at a point beyond an end of said output shaft, means biasing said trip arm toward a neutral position in which it is spaced from both of said latches, a gear rotatably mounted on said second portion of said trip arm above and for rotation about an axis perpendicular to the extended axis of said output shaft, a feedback gear and a drive gear mounted in spaced apart relation for rotation about the extended axis of said output shaft and engaging the gear on said trip arm, a dead-space coupling connecting said feedback gear to said output shaft, and an input shaft fixed to said drive gear.

11. The combination which comprises a rotatable member, means for applying a force tending to rotate said member, stop means mounted adjacent said member for movement between a first position in which it is in holding engagement with the surface of said member to prevent rotation thereof and a second position in which it is out of holding engagement with respect to said member, means biasing said step means toward said first position, control means for moving said stop means to Said second position, said control means including a control element movable between a normal first position in which said control means is not effective to move said step means and a second position in which said control means is effective to position said stop means in its second position, means for supplying an input signal to said control means, means operatively connected to said rotatable member for supplying a feedback signal to said control means corresponding to the extent of movement of said rotatable member, and means responsive to both of said signals for moving said control element, whereby, when an input signal of predetermined magnitude is supplied to said control means, said control element will move to said second position thereof and said stop means will move to said second position thereof to permit movement of said rotatable member under the influence of said force, which movement will cause a feedback signal to be fed to said control means to return said control element to said normal first position thereof.

12. In a servo-mechanism, the combination which comprises a movable member having a plurality of teeth thereon, a source of mechanically stored energy operatively connected to said member for continuously applying a force thereto tending to move said member, stop 8 means mounted adjacent the path of movement of said teeth for movement between a first position in which it is in holding engagement with at least one of said teeth to prevent movement of said member and a second position in which it is out of holding engagement with said teeth, means biasing said stop means toward said first position, means for supplying an input signal, means operatively connected to said movable member for supplying a feedback signal corresponding to the extent of movement of said member, and control means responsive to both of said signais for moving said stop means to its second position in response to an input signal of predetermined magnitude and for permitting the return of said step means to its first position in response to a feedback signal corresponding to a movement of said movable member equal to the distance between successive teeth thereon.

13. A servo-mechanism comprising a rotatable output shaft, first and second rotatable members each having a series of angularly spaced teeth extending about the axis of rotation thereof, means for mechanically storing energy operatively connected to said members to apply forces thereto tending to rotate said members, first and second stop means cooperating respectively with the teeth on said first and second members, each of said stop means being biased toward a first position in which it is in holding engagement with at least one tooth on a rotatable member but being movable to a second position in which it is out of holding engagement with respect to such member, means operatively connecting said first and second rotatable members to said output shaft for rotating said shaft in one direction upon rotation of said first member and in the opposite direction upon r0- tation of said second member, means for supplying an input signal, means operatively connected to said output shaft for supplying a feedback signal corresponding to the extent of angular movement of said output shaft, and control means responsive to both of said signals for moving either of said stop means to its second position in response to an input signal of predetermined magnitude and for permitting the return of such stop means to its first position in response to a feedback signal corresponding to the output shaft movement produced by movement of one of said rotatable members through an angular distance corresponding to the space between successive teeth thereon.

14. The combination which comprises a movable member, a source of mechanically stored energy operatively connected to said member and continuously applying a force to said member tending to cause said member to move, stop means movable between a first position in which it contacts said member to prevent movement of the member and a second position in which it is out of contact with said member, means for moving said stop means from said first position to said second positionto free said movable member for motion under the influence of the force applied by said source of mechanically stored energy, and means operable in response to movement of said movable member for returning said stop means to said first position.

References Cited in the file of this patent UNITED STATES PATENTS 1,377,844 McCutchen et al. May 10, 1921 2,078,161 Rietsch Apr. 20, 1937 2,266,237 Newell Dec. 16, 1941 2,542,088 Krieger Feb. 20, 1951 2,551,943 Gulow May 8, 1951 2,625,619 Rigert Jan. 13, 1953 2,738,390 Bentley Mar. 13, 1956 

